Reclaiming spent oil



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Patented Dec.. E99 lltlldll latent WARNER STUTLER, @FIBENNING RUAD AND DISTRCT LENE; EDISTR'ECT 0F CLTMBXA, .rhSSG-NOR T0 WARNER STUTLER COMPANY, INC., 0lq1 WASHXNGTON, DIESTFCT 0F CLUMBL'A, A GORPORATOI DI@ THE VEVJ'lL'S'lllRCi." COLUIVIBEA .esoneri/nue sentir-'ort application filed; December 123, 15H39. Serial No.y 4:13,@99.

'llhis invention relates to a process ot reclaiming spent lubricating oil, such as used oil from internal combustion engines.

The principal object of this invention is to provide a simple, eiiicient and economical process wherebyl spent or used lubricating oil, such as that which is drained from the cranlr case of an automobile after it has become unsuited for further use may be purified,cleansed, and converted into a utilizable product. n

@ther objects and advantages of the invention will become apparent duringthe course Ioi the following description.

lteclaimingof used lubricating' oil has for a number of years attracted the attention ot many persons, and many methods have been devised in an attempt to remove from used oils deleterious substances such as gasoline fractions which reduce the viscosity of the oil, solid'suspended matter which due to its abrasive action renders the oil unsuitable for lubricating purposes, and acid forming substances such as Water. However the reclaimed' oils produced by these processes have not proved thoroughly satisfactory.

ll have discovered that if used oils are lirst clarified and subsequently distilledA with agitation a materially improved character of product is obtained. Such process includes the primary treatment of the used oil With Water together with a clarifying agent, and the subsequent fractional distillati n of the thus clarified product either withoi further treatment or in conjunction with a bleaching agent as hereinafter described.

lnthe preferred practice" of this invention a substantially large quantity of used or spent lubricating oil for instance, approximately 300 gallons, is mixed with approximately from 30 to 75 gallons of Water and steam `is passed through the body of such mixture until the temperaturefthereof is raised approximately to the boiling point of Water Which condition is evidenced by the appearance of steam coming ofi' from the top of the oil under treatment. Such temperature having been reached a' clarifying agent is added tothe material to precipitate Ithe impurities therein. Numerous clarifysatisfactorily approximately 300 gallons of oil. l/l-hen, as in the preferred embodiment ot the-invention, commercial soda ash is used l have found that best results are obtained it approximately 75 pounds of this material are used to treat 300 gallons of oil. ln the actual practice of the process th used oil and Water are mixed in any suitable container and steam under a pressure of approrimately 8'()` pounds per square inch is introduced into the mixture, preferablyadjacent the bottom of thecontainer. By this procedure the steam acts not only to heat up the mass but at the same time serves to agitate it whereby the use of agitators is avoided, as would be required if the conftainer were externally heated. After the mass has been heated until the steam begins to rise from the top of the liquid the clarifying agent is added and the resulting mass ,is heated to a temperature of approximately from 225 to 300o F. when the steam is out oli'. The mass is then allowed to stand until the clarifying agent has caused the precipitation or settling of substantially all. O the solidV content in the oil. This is accom- Y plished by the. adhering of the clarifying agent to the fine particles of solid matter whereby lthese particles settle relatively rapidly and do not remain in' suspension as would, to a great extent, be the case if the clarifying agent Were not employed. n the preferred practice the heated mass` is permitted to stand overnight although in some instances standing for 5 hours is suiiicient. l The thus clarified oil is drawn-oit and introduced into a still or similar apparatus Where it is heated in the manner hereinafter ing agents may be employed in the practice GFI described to drive off. the lighter fractions of the oil and regulate the viscosityv of the final' product. Broadly speaking, the oil is heated in the still for approximately from two hours tothree hours at a temperature of approximately from 500 to 650. F. and after the temperature of the oil has reached approximately 300 F. it is preferable to introduce steam into the lower portion, of the still and continue its introduction during the heat treatment. In conducting the heat treatment it is important that care be taken to preventany substantial cracking of the oil.

rlfhe light ends and steam which are driven off during the distilling process are discharged from the still and passed through a condenser whereby the light ends may be recovered for use, particularly as a penetrating oil or fuel oil.

After repeated experiments I have found that materially improved operating conditions and a substantially improved product are obtained if the heat treatment is conducted in a relatively elongated, upright still provided with agitating means arranged adjacent the lower portion thereof which are so designed as to provide a whirling or rotary motion of the oil around the central vertical axis of the still and at the same time to provide a current of the oil which is upward adjacent the periphery of the still and downward toward the central portion of the still. While I do not undertake to advance any theory for the improved results which are obtained by conducting the heat treatment in the specific manner described, tests are convincing that greatly improved results are obtained as a direct result of this treatment.

At the completion of the heat treatment the oil is drawn off from the still and is cooled, as by running it through cold pipes,

after which the oil is in condition for re-use as a lubricating oil. The oil is unbleached butthis does not impair its lubricating qualities in any way. j However, if a bleached oil is desired this may be readily accomplished by introducing a bleaching agent into the oil during the process. For example, a bleached product may be obtained by adding a bleaching earth such as bentonite, metalloid or the like, to the partially purified oil prior to its introduction into the still, and passing the oil after heat treatment thereof through a filter press to remove thesolid particles vof the bleaching earth and coloring matter associated therewith. The particular advantage of introducing the bleaching agent into the oil prior to the distilling thereof is that a particularly intimate contact of the bleaching agent with the oil is provided by the agitation in the still. The bleaching. agent may be used in varying amounts but I have found that particularly advantageous results are obassente tained by employing one pound of bleaching agent to each gallon of oil treated.

As indicated above, the viscosity of the final product may be regulated according to the time and temperature of the heat treatment of the partially purified oil in the still. This is important particularly in the treatment of oil intended for use as crank case oil for automobiles since motorists demand several grades of oil as regards to viscosity, such as light, medium and heavy oil. Generally speaking, these three types of oil correspond to oils having an S. A. E. viscosity of 30, 40 and 50.

An S. A. E. 30 oil may be obtained in the practice of my process by conducting the heat treatment referred to above at a temperature of approximately 50,0o F. for approximately 2 hours. By heating the oil to approximately from 550O to 600o F. for about two and onehalf hours an S. A. E. 40 oil is obtained. Treatment at from approximately 600o to 650 F. for about three hours results in the production of an S. A. E. 50 oil.

In the accompanying drawings, I have indicated one embodiment of apparatus suitable for use in the practice of my process. ln the drawings,

Figure 1 is a diagrammatic flow sheet of the process, j

Figure 2 is a detail elevation of a preferred form of still with the wall thereof partly broken away, and,

Figure 3 is a transverse line 8-3 of Figure 2.

In the practice of my process in the form of apparatus, indicated in the accompanying drawings, spent or used oil to be treated is introduced into a clarifying and settling tank 1 as at the point 2. The required amount of water is introduced as at the point 3 into the tank 1 and the mixture of oil and water is heated in the manner described above with steam admitted as at 4 through a pipe (not shown) which preferably extends into the tank and terminates in an open-end or nozzle at a point adjacent the bottom of the tank. When the mixture of oil and water has been section taken on .heated to the desired temperature, as indicated above, a clarifying agent is introduced into the tank 1 as at the point 5. When the mass in the tank 1 has been heated to the desired temperature the steam is cut off and the mass allow-ed to stand until the impurities have Vsettled to the bottom of the tank.

When the clarifying and settling operation has been completed the lsettlings are removed through a pipe 6 and the clarified and partiallypurified oil is conveyed from the tank 1 through a pipe 7 Iinto a still 8 where the oil is heated in the manner described above in the presence of steam which is preferably introduced into the still as at 9. The vapors driven off from the still during the heat treatment are conducted through a pipe a propeller 2l.

Lasarte 10 to a condenser 11 where these vapors are condensed and recovered as a light oil. At the completion off the heat treatment, the oil remaining in the still is drawn off through a a, pipe 12 and introduced into a cooler 13 from which the oil is discharged asiat 14 after the cooling operation has been completed.

its stated above, it is sometimes desirable Vto produce a bleached vor light colored oil andr in such event a bleaching agent of the the practice when no bleaching agent is em-k ployed, the oil and the bleaching agent asson ciated therewith are withdrawn as at 16 and passed through a filter press 17 to remove the solid particles present, after which the light colored oil is withdrawn as at 18 for use as desired..

its stated above, l have found that greatly improved results are obtained if the heat treatment is conducted in a relatively elongated, upright still provided with agitating` means arranged adjacent the lower portion thereof which are so designed as to provide a whirling or rotary motion of the oil around the central vertical axis of the still and at the Sametime to provide a current of the oil which is upward adjacent the periphery of the. still and downward'. toward the central portion of the still. ln Figures 2 and 3 of the drawings l have illustrated a type of still which is particularly adapted for use in the practice of my process.Y ylhis still is designated generally by the referencentuneral 20 and comprises an elongated cylinder closed at both ends. cylinder is a'ected primarily by means of During the heating and agitating of the oil steam is admitted through a pipe and steam coil 22. rlhe still is heated in any suitable manner but preferably by means of an oil burner, designated generally by thereference numeral 23, arranged in the fire-box 32.

The rotation of the propeller 21 is effected by means of a shaft 24f to theupper end lof which -is secureda bevel gear 25 meshing with4 a suitable gear 26 carried bythe shaft 27 which is driven by any suitable/source of power (not shown). The shaft 24 is `carried in bearings 28 and 29 arranged in the upper and lower'walls- 30 and 31. rlhe propeller 21 preferably consists of blades 33, 34, 35, and 36 which are so designed as to providey a whirling motion of the oil around'the shaft 24'and also to provide an upward and downward current of oil in the manner described above and as indicated by the arrow in Fig- 'lhe' agitation of the oil in the ure 2. rlhe vapors driven od from the oil during the heat treatment are discharged through the pipe 37 provided with a valve 38. rlhe apparatus just described constitutes the preferred form of apparatus to be used in the practice of my process but it is to be understood that other forms of apparatus may be used if desired.

wl/ll/vhether the process is conducted so as to provide either a bleached or an unbleached/ product, the oil produced will be/fo'und to be wholly satisfactory for reuse as a lubricant. In some instances, the oil will be found to be superior to the original oil due to the removal of impurities, such as certain unsaturated compounds, which have been broken down by the heat of the engine lubricated by the original oil. Moreover, any impurities present which will react with the carifgying agent employed to form insoluble compounds will be separated from the oil together with particles of carbon, dirt, metal particles and like solid impurities which serve to impair the lubricating properties of the oil. .Moreoven any water present in the oil treated will be driven off and a high grade oil of the desired viscositywill be produced.

Vl/'hi'le li have described'in detail the preferred practice of myrprocess and a preferred form of apparatus to be used, it is to be understood that the details of procedure and the form of apparatus may be variously modied Without departing from the spirit of the invention or the scope ofthe subjoined claims. lf claim:

1. The herein described process of reclaiming spent lubricating oil which comprises heating the oil'in the presence of water and an alkaline clarifying agent to a temperature of approximately from 225 to 3000 F., periitting the resulting mass to stand to effect clarification of the oil, distilling the oil in the presence of steam' and a bleaching agent while agitating the oil to drive off relativelyl low boiling hydrocarbons and to effect intimate contact between the oil and bleachng agent, and filtering the resulting oil to remove therefrom the bleaching agent and associated coloring matter. f

i 2. rll'he herein described process of reclaiming spent lubricating oil which comprises heating the oil in the presence of water and a clarifying agent, permitting the massto stand to effect clarification of the oil, distilling the oil in the presence of steam in an t A 3. The herein described process of reclaimingspent lubricating oil which comprises heating the oil in the presence of water and a clarifying agent, permitting'the mass to stand to 'effect clarification of the oil, distilling the oil in the presence of steam and a bleaching earth in an upright column, the steam being introduced adjacent the lower 'portion of said column, while agitating the oil in such manner that a whirling motion of the oil is secured and a current of oil is provided which is upward adjacent the outer portion of the column and downward adjacent the central vertical axis of the column, i

and iiltering the resulting oil which has been substantially freed fromlight ends present by the distillation operation to removetherefrom the bleaching earth and associated coloring matter.

4. The herein described process of reclaiming spent lubricating oil which comprises heating and agitating the oil in the presence of water by means'of a current of steam under pressure, adding soda ash to the mass, and heating the resulting mass to a temperature of approximately from 225-to 300o F., permitting the resulting mass to stand t0 effect clarification thereof, heating the resulting oil in the presence of steam and a bleaching earth in an upright column at a temperature of approximately from 500 to 650 F. for approximately from 2 to 3 hours, while agitating the oil in such manner that a whirling motion of the oil is secured and a current of oil'is provided which is upward adjacent the outer portion of the column and downward adjacent the central vertical axis of the column, to drive oft' light ends present in the oil and Asimultaneously bleach the same, and passing the resulting oil through a filter press to remove solids therefrom.

In testimony whereof afiX my signature.

WARNER STUTLER. 

